The main picture below shows eight shelves of six foot board. This will hold a grand total of about 960 movies. This is what I will be describing in this instructable.
The second picture is a five foot wide with six staggered shelves version. While slightly more complicated, it should be easy to figure out after this instructable.
The basic idea is that I would use heavy duty hooks, steel cable, and wood shelves to build it (basically cheaper stuff that I can find at home depot). The wire would fit into a groove that I cut and I would use a stopper fastener on the wire to keep it in place.
Keep in mind this is just hanging on the wall, and can move, so don't put anything really breakable on it. Especially with little ones around.
Check out my other industrial shelves for a complete set: Equipment Shelves and TV Ledge